Field of the Invention
This invention relates generally to dual-display devices and, more particularly, to using a crossbar switch to select one of multiple dual-display modes.
Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
All-in-one computing devices are computing devices that include both a graphics-processing unit (GPU) and a display device. Tablets and laptops are typically all-in-one devices, and some desktop devices are designed as all-in-one devices. The GPU may be part of a central processing unit (CPU) or may be a separate device from the CPU. Current graphics processing units (GPUs) and operating systems (OS) (e.g., Microsoft® Windows®) are pre-configured to drive a single, internal display device using an embedded DisplayPort (eDP) port. For this reason, content displayed on the internal display device is automatically rotated while content displayed on an additional display device (e.g., considered by the GPU and operating system as an external display device) is not automatically rotated. The eDP port is designed to (a) output media content without digital rights management (DRM) (e.g., High-bandwidth Digital Content Protection (HDCP)) when outputting protected content to an embedded display (e.g., an internal display) and (b) encrypt content using DRM (e.g., HDCP) before outputting to the additional display.
However, the presumption by the GPU and OS that the computing device has a single internal display device can cause problems when an all-in-one computing device has two (or more) display devices which are both internal to (e.g., incorporated into) the computing device. For example, if a computing device includes two display devices, an eDP port may drive the first display (internal display) device while a DisplayPort (DP) port may drive a second display (additional or external display) device. In this example, protected content may be displayed on the first display device but not on the second display device because the second display device does not have the circuitry to decrypt encrypted (e.g., HDCP) content, even though the second display device is an embedded display device that does not expect to receive encrypted content. Therefore, an all-in-one computing device that has two (or more) display devices may have problems (1) playing DRM protected media content and (2) changing the orientation of content being sent to each of the display devices.